Referring to FIGS. 6 and 7, a pair of conventional brake devices 9 are respectively pivoted to two frame bars 84 of a frame fork 8 of a bicycle (not shown) by pivot bolts 82. A washer 99 is disposed on each pivot bolt 82. The brake device 9 is normally an L-shaped brake arm 92 with a brake shoe 94 fixed thereon. The free ends of the brake arms 92 are connected and actuated by a cable 88. When pulling the cable 88 by a brake handle (not shown), the brake arms 92 rotate about the pivot bolts 82 towards a wheel 80 such that the brake shoes 94 press the rim 81 of the wheel 80, thus accomplishing the braking purpose. However, when the cable 88 is broken, the brake arms 92 rotate outwards and tend to be suspended as shown in imaginary lines in FIG. 6 because of the gravity, such that the free ends of the brake arms 92 interfere the wheel spoke (not shown) of the wheel 80. This is very dangerous when the bicycle is moving at high speeds.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the brake device of the bicycle.